Cast Sandbar Merfolk from your graveyard by paying {U}.
Activate Phyrexian Altar by sacrificing Sandbar Merfolk, adding {U}.
Sandbar Merfolk is not exiled by Abandoned Sarcophagus due to Dress Down removing Sandbar Merfolk's cycling ability.
Repeat.

Infinite death triggers

Infinite creature ETB

Infinite creature LTB

Infinite creature sacrifice triggers

Infinite storm count

Abandoned Sarcophagus

Phyrexian Altar

Sandbar Merfolk

Dress Down

Cast Sandbar Merfolk from your hand or graveyard by paying {U}.
Activate Phyrexian Altar by sacrificing Sandbar Merfolk, adding {U}.
If Sandbar Merfolk was cast from your graveyard, Sandbar Merfolk is not exiled by Abandoned Sarcophagus due to Overwhelming Splendor removing Sandbar Merfolk's cycling ability.
Repeat.

Overwhelming Splendor

Cast Sandbar Merfolk from your graveyard by paying {U}.
Activate Phyrexian Altar by sacrificing Sandbar Merfolk, adding {U}.
Sandbar Merfolk is not exiled by Abandoned Sarcophagus due to Humility removing Sandbar Merfolk's cycling ability.
Repeat.

Humility

Cast Sandbar Merfolk either from your hand or from your graveyard by paying {U}, causing it to enter the battlefield as a copy of Crosis's Attendant due to Infinite Reflection.
Activate Sandbar Merfolk by paying {1} and sacrificing it, adding {U}{B}{R}.
If you cast Sandbar Merfolk from your graveyard, Sandbar Merfolk is not exiled by Abandoned Sarcophagus due to Infinite Reflection removing Sandbar Merfolk's cycling ability.
Repeat.

Infinite black mana

Infinite red mana

Infinite Reflection

Crosis's Attendant

Cast Sandbar Merfolk either from your hand or from your graveyard by paying {U}, causing it to enter the battlefield as a copy of Morgue Toad due to Infinite Reflection.
Activate Sandbar Merfolk by sacrificing it, adding {U}{R}.
If you cast Sandbar Merfolk from your graveyard, Sandbar Merfolk is not exiled by Abandoned Sarcophagus due to Infinite Reflection removing Sandbar Merfolk's cycling ability.
Repeat.

Morgue Toad

Cast Sandbar Merfolk either from your hand or from your graveyard by paying {U}, causing it to enter the battlefield as a copy of the creature with Infinite Reflection attached.
Activate Phyrexian Altar by sacrificing Sandbar Merfolk, adding {U}.
If you cast Sandbar Merfolk from your graveyard, Sandbar Merfolk is not exiled by Abandoned Sarcophagus due to Infinite Reflection removing Sandbar Merfolk's cycling ability.
Repeat.

Cast Sandbar Merfolk either from your hand or from your graveyard by paying {U}, causing it to enter the battlefield as a copy of Verdant Eidolon due to Infinite Reflection.
Activate Sandbar Merfolk by paying {G} and sacrificing it, adding {G}{G}{G} or {U}{U}{U}.
If you cast Sandbar Merfolk from your graveyard, Sandbar Merfolk is not exiled by Abandoned Sarcophagus due to Infinite Reflection removing Sandbar Merfolk's cycling ability.
Repeat.

Infinite colored mana

Verdant Eidolon

Cast Sandbar Merfolk either from your hand or from your graveyard by paying {U}, causing it to enter the battlefield as a copy of Treva's Attendant due to Infinite Reflection.
Activate Sandbar Merfolk by paying {1} and sacrificing it, adding {G}{W}{U}.
If you cast Sandbar Merfolk from your graveyard, Sandbar Merfolk is not exiled by Abandoned Sarcophagus due to Infinite Reflection removing Sandbar Merfolk's cycling ability.
Repeat.

Infinite green mana

Infinite white mana

Treva's Attendant

Cast Sandbar Merfolk either from your hand or from your graveyard by paying {U}, causing it to enter the battlefield as a copy of Dromar's Attendant due to Infinite Reflection.
Activate Sandbar Merfolk by paying {1} and sacrificing it, adding {W}{U}{B}.
If you cast Sandbar Merfolk from your graveyard, Sandbar Merfolk is not exiled by Abandoned Sarcophagus due to Infinite Reflection removing Sandbar Merfolk's cycling ability.
Repeat.

Combos with "Sandbar Merfolk"